1. Field of the Invention
This invention relates to a headlight assembly, more particularly to a projector-type vehicle headlight assembly.
2. Description of the Related Art
A vehicle headlamp assembly is configured to provide road illumination to suit different road conditions and road visibility requirements. Currently, there exists a projector-type, or Poly-Ellipsoid System (PES) headlamp assembly. FIG. 1 shows a conventional headlamp assembly, which includes a reflector 61 that defines a compartment 610, a light source 62 mounted in the compartment 610 and disposed on an optical axis (x), a lighting shielding plate 63 extending upwardly from a bottom edge of the reflector and having a top edge that is flush with the optical axis (x), a housing (not shown) assembled in front of the reflector 61. By virtue of the shielding effect of the light shielding plate 63, the light beams reach and exit a region of the lens 64 that is below the optical axis (x). As a result, an illuminating pattern is formed. Even though the aforementioned vehicle headlamp assembly is capable of casting the illuminating pattern, the pattern cast thereby is heavily concentrated at a lower region (i.e., below the optical axis “x”), and causes an adjacent upper region (i.e., above the optical axis “x”) to suffer from inadequate light illumination.
In order to adequately illuminate on upper region that is 18 meters in front of the headlamp assembly, the headlamp assembly must be able to provide at least 64 candela (cd) of light intensity thereat. However, the aforementioned conventional vehicle headlamp assembly does not have enough power to cast such light intensity, which is detrimental for drivers to be not able to discern the overhead signs when driving at nighttime.
As illustrated in FIG. 2, U.S. Pat. No. 6,736,533 discloses a vehicular headlamp that has an auxiliary plate 72 provided in front of a shield plate 71. The auxiliary plate 72 serves to reflect a portion of the descending light beams through a lens 73. As a result of passing through the lens 73, light beams A1 radiate forwardly in an upward direction so as to enhance overall light intensity in the upper region. Referring to FIG. 3, U.S. Pat. No. 6,736,533 further teaches another vehicular headlamp that has an aperture 810 in the shield plate 81, and an auxiliary plate 82 provided on an inner side of the shield plate 81. This particular configuration can also achieve the effect of enhancing light intensity in the upper region.
Another conventional headlight is disclosed in U.S. Patent Application Publication No. 2001/0019484, which discloses a screen configuration that permits limited upper region illumination.